Rearview mirror

Abstract

A rearview mirror for passenger vehicles has a primary viewing surface that is substantially flat. This surface curves to the rear of the mirror, with a continuously decreasing radius of curvature, toward at least one lateral edge thereof. This provides peripheral vision to the operator of a vehicle in addition to this vision directly to the rear. The peripheral vision introduces a very gradually increasing rate of distortion as the reflected image approaches the edge of vision. This causes the peripherally reflected images to be easily relatable to those reflected from the primary viewing surface.

I claim: 
     
       1. A mirror having a substantially flat, primary viewing surface, said primary viewing surface having a border merging substantially tangentially into an edge viewing portion which curves away from said primary viewing surface, said edge viewing portion having a cycloidal curvature having a continuously decreasing radius of curvature from the border of said primary viewing surface to the outer edge of said edge viewing portion. 
     
     
       2. A mirror as defined in claim 1, in which said edge viewing portion forms a segment of a surface of revolution developed by revolving said cycloidal curvature about an axis substantially normal to said primary viewing surface. 
     
     
       3. A mirror having a substantially flat, primary viewing surface, said primary viewing surface having a border merging substantially tangentially into an edge viewing portion which curves away from said primary viewing surface, said edge viewing portion having a curvature developed by projecting at right angles to a major axis successive positions, equally spaced angularly, of a point on the circumference of a circle rolling along said major axis, and tracing the curve defined by intersections of successive projection lines of the point perpendicular to said major axis with successive equally spaced lines parallel to said major axis. 
     
     
       4. The mirror of claim 3 wherein the curved portion thereof is defined by projections, throughout a maximum angular displacement of about 90°, of the point positions on the circumference of the rolling circle, beginning with the position of the point on the major axis. 
     
     
       5. A mirror having a substantially flat primary viewing surface, said primary viewing surface having a border merging substantially tangentially into an edge viewing portion which curves away from said primary viewing surface, said edge viewing portion having a curvature conforming to a portion of an ellipse and having a continuously decreasing radius of curvature from the border of said primary viewing surface to the outer edge of said edge viewing portion. 
     
     
       6. A mirror as defined in claim 3, in either which the primary viewing surface has a linear border and the edge viewing portion curves away from said linear border. 
     
     
       7. A mirror as defined in either claim 3 or 5, in which the primary viewing surface has a circular border, and the edge viewing portion forms a segment of a surface of revolution developed by revolving the curvature of the edge viewing portion about an axis normal to said primary viewing surface.